Higher bandwidth requirements for imaging, broadcasting, weather forecasting, and other commercial and military applications increase the need for faster, more robust satellite communications. Current state-of-the-art satellite communication systems have been unable to keep up with the increased demand due to various limitations. For example, conventional satellite systems operate in single-input-single-output (SISO) mode, where a single information-bearing signal is transmitted from ground to space or space to ground. SISO communication links have data rates that are fundamentally limited by their allocated bandwidth, their transmit power, and their antenna sizes. SISO communication capacity grows only logarithmically with the transmitted power and antenna size, thus requiring installation of more powerful and expensive satellites to achieve increases in data capacity.
While efforts have been made to enhance reliability and performance of satellite networks using terrestrial relay stations, current proposals introduce several vulnerabilities. For example, proposed satellite communication networks that employ terrestrial relay points may require protected ground nodes to assure data security and integrity, large and expensive antennas, or may be susceptible to adverse weather conditions.
To meet the escalating demand for higher data rates, a more scalable satellite communication system is therefore needed. It would also be desirable to achieve higher data capacity in satellite communications while limiting vulnerabilities to adverse weather conditions, high costs of multiple relay satellites, and degradation to data security and integrity of conventional systems.